In 1996, Assistive Technology Inc. of Dedham, Mass. introduced the Companion software (CSUN Conference). Companion was based on animated pictorial scenes, with the idea that finding single meaning vocabulary in a contextual presentation would be successful in teaching the cognitively impaired. Four publications discussing the use of VSDs in such a context include:    Light, Drager, Speltz, Fallon & Jeffries. The Performance of Typically Developing 2½ Year-Olds on Dynamic Display AAC Technologies With Different System Layouts and Language Organizations (VSD vs. Grid, all page-based), Journal of Speech, Language and Hearing, Volume 46, April 2003, pp. 298-312;    Light, Drager, McCarthy, Mellot, Millar, Parrish, Parsons, Rhoads, Ward, Welliver. Performance of Typically Developing Four- and Five-Year-Old Children with AAC Systems using Different Language Organization Techniques (VSD, Page-based & Minspeak) AAC, Volume 20, June 2004, pp. 63-88;    Drager, Light, Carlson, D'Silva, Larsson, Pitkin, Stopper. Learning of Dynamic Display AAC Technologies by Typically Developing 3-Year-Olds: Effect of Different Layouts and Menu Approaches (VSD vs. Grid, all page-based), Journal of Speech, Language, and Hearing Research, Volume 47, October 2004, pp. 1133-1148; and    Light, Drager. AAC to Improve Language, Literacy, and Communication Outcomes for Young Children with Complex Communication Needs, AAC-RERC State-of-the-Art Whitepaper 2006.
In one example, a VSD master page such as that of FIG. 1A for example, included a house with four rooms 1a-1d (each a miniature version of the target scene). A VSD page could then be accessed from the master page of FIG. 1A for example, as shown by the selection square 2 encompassing and selecting room 1d. Then, the display of FIG. 1A would be replaced by an enlarged version of the selected room as shown in FIG. 1B for example. The selected room of FIG. 1B would then include vocabulary ‘hot spots’ (portions of the picture that could be selected by being touched or activated to provide at least one of an audible and visual response including the present 3a, the boy 3b, the cat 3c, etc.).
The data showed that children generally could not find the correct page in grid-based page systems:
Chance of randomly selecting correct page was ¼; and
Children's average accuracy in selecting correct grid page: ˜¼.
Children had difficulty either identifying the correct page or identifying the link from the menu page to the target page. Children did slightly better in the overall task with the VSD-based system, but still found less than ¼ of the words. In the VSD condition, children scored an average of 2.6 of 12 correct responses across 4 sessions. In the taxonomic grid condition, children scored about 1 of 12. In the activity-based condition, children scored about 1.4 of 12.
All conditions in both studies were page-based single meaning pictures. Further, the results of the articles indicated that 2½ and 3-year-old children performed poorly on both traditional page-based systems and VSD page-based systems. The studies were not well-designed to address language acquisition models, but focused on conscious learning of the location of words already known to typically developing children.
Traditional page-based systems included pages of grids grid representations with small individual pictures representing vocabulary. Grid representations were a collection of individual symbols/pictures that represent vocabulary items and were used to teach, at best, individual vocabulary words.
None of the page-based arrangements (grid or VSD) was initially transparent to the children in these studies. The children performed poorly in all page-based single meaning picture conditions but were able to locate slightly more vocabulary items in the VSD condition than in the grid-based approaches. Although the VSDs were initially used, the studies found that the children had to move away from the VSDs as soon as possible, to a standard grid type single meaning display.
Thus, VSDs are currently not being proposed for independent generative communication on the device. If person using a communication aid is trying to find vocabulary to communicate meaning, which VSD page is he or she going to look for? How can that person find that page? VSD usage is heavily dependent on a therapist or communication partner. The therapy structures proposed by Light are both clinician-intensive and clinician-driven. The cost of learning in transitions to/from VSDs to any other format on the device is very high. Clinicians are unclear as to how to bridge the gap from VSDs to spontaneous language generation and independent communication. Generating language on the device to model language acquisition as discussed by R. Brown, R. Paul, L. Bloom does not seem to be the goal of VSDs.